The Internet has become ossified due to its strong support of numerous activities of our society and the fact that it was not defined with the current vision of a business and societal infrastructure. For example, despite international support and strong technical motivation to migrate, IPv6 has not been widely deployed yet. The reason is that the basic concept of the Internet as an end-to-end packet delivery service has made its middle layer, networking services through TCP/IP, untouchable. To test any disruptive enhancements to security, routing flexibility and reliability, and robust quality of service guarantees in coming years, an Internet environment is needed where networking environments offering differing strengths can coexist on a permanent basis.
The Global Environment for Networking Innovation (GENI) is a US national shared experimental facility for future Internet research. One application-specific agile virtual network (namely slice) enables user defined experiment to run on GENI. In each slice, the virtual topology consisted of multiple virtual links (in contrast to physical links in GENI). Each virtual link not only provides connectivity (in addition to delay or packet loss ratio or even protection constraints), but also requires guaranteed bandwidth (arbitrary bandwidth granularity) for highly fidelity experiments. Due to multiple experiments running on one physical GENI substrate simultaneously, all resources including router bandwidth, processing computing cycles, and storage capacity should be sliceable.
In GENI, the routers play key roles for bandwidth virtualization, forwarding user packets, and computing routes. Thus, the problem of router bandwidth (or interface) virtualization for providing various kinds of virtual links is becoming a basic problem in GENI. The requirement of virtual link should be programmable, reconfigurable, and bandwidth guaranteed.
A conventional router usually provides several types of transmission pipe, e.g., Packets over SONET/SDH (POS), Gigabit Ethernet or 10 Gigabit Ethernet (GE/10GE) optical interfaces, which are mainly based on TDM/TDMA. Currently, there are already several applied methods for providing virtual interfaces or virtual links in GENI, most of them are based on software tunnels (only providing connectivity, no bandwidth guaranteed), including:                Lightpath (Optical Wavelength Path)        TDM circuit (SDH/SONET/MSTP, e.g., OC-3/STS-1)        ATM VC/VP        Ethernet VLAN tunnel        MPLS labeled switched path (LSP)        IP tunnel (e.g., GRE)        UDP tunnel        
The above conventional solutions are based on TDM/TDMA, which means all slices share the bandwidth resources in time domain. Generally speaking, the time-domain sharing solutions for bandwidth virtualization are rigid, complicated (e.g., scheduling), and inapplicable to highly bursty applications.